We are conducting a randomized, double blind placebo controlled study of surgery with or without raloxifene for treatment of pain from endometriosis. Women with chronic pelvic pain and no endometriosis treatment for 6 months undergo laparoscopic excision of endometriosis lesions after monitoring pelvic pain for 1 month. Those with biopsy-proven endometriosis are randomized to daily raloxifene (180 mg) or placebo for six months. Return of pain is defined as 2 months of pain severity equal to that at study entry. Women have a second surgery at 2 years, or when pelvic pain returns earlier. In the most recent review by the Data Safety and Monitoring Board (DSMB), the study was stopped early because those treated with raloxifene experienced return of pain significantly sooner than those taking placebo and had 2nd surgery sooner. At that time, 93 of 127 women who had undergone surgery had biopsy positive endometriosis and were randomized. In the next year we will analyze the study outcome results including the effect of raloxifene on menstrual cycle length and adverse events during treatment. It appears that raloxifene taken after complete excision of endometriosis significantly shortened the time to return of pain. As part of this clinical trial, we have explored other aspects of endometriosis. To date, we have examined the utility of MRI in diagnosing endometriosis, showing that MRI has a low detection rate of biopsy-proven endometriosis lesions and is relatively insensitive in determining whether a woman has endometriosis. We recently postulated that persistence of dysmenorrhea and nonmenstrual pelvic pain at three months after excision of endometriosis might be associated with adenomyosis as defined by a thickened uterine junctional zone on magnetic resonance imaging. If it is, this suggests myometrial junctional zone abnormalities or adenomyosis may contribute to chronic pelvic pain in women with endometriosis. Migraine headaches and chronic pelvic pain associated with endometriosis, commonly affect reproductive aged women. We have recently hypothesized that these two chronic, debilitating conditions might co-occur. In our preliminary review of patients enrolled in the clinical trial, at least two thirds of women with chronic pelvic pain have migraine headaches that appear to be independent of endometriosis diagnosis. We will examine whether quality-of-life is lowered, beyond that due to pelvic pain alone. If migraine headache is common in women with chronic pelvic pain, regardless of the presence of endometriosis, it may contribute to disability of those with both conditions and may suggest a common pathophysiology.